Telephone system



July '7, 1931. 0. E. BEALE TELEPHONE SYSTEM Filed Odc. l. 1928 3 Sheets-Sheet 1 5 a & L1

Charles Edmund Beale July 7, 1931. c. E. BEALE TELEPHONE SYSTEM Filed Oct. 1. 1928 3 Sheets-Sheet 2 'July 7, 1931. I

c. E. BEALE TELEPHONE SYSTEM Filed Oct. 1, 1928 s sheets-Sheet cs l R i 3 3 \1 "i i I lg 2 l h) Q i F A.

Charles Edmund Beale lf-E Patented July 7, 1931 CHARLES EDMUND BEALE, or nonnonfnncrnnng Assidnoa '10.- ASSOCIATED "remn- PHQNE AND TELEGRAPH comranruorrmnsas: orrxymrssoum; aoonronn'rrou switches, cxample,jthis or DELAWARE 'rnnnrrrenn SYSTEM p Application filed October 1,1923, Serial 110,609,649, and m Great Britein November 23,1927.

The present invention relates'to systems and' is more particularly. concerned with systems employingswitches of the so called drop back type, that is, switches which automatically return to normal-upon receipt of a digit of critical value, While the, invention has also wider application,

its use is particularly advantageous in a private branch exchange system employing 100, or 200-point switches, and comprising the first case l00'linesl or less, and in the second case comprising 200 lines or less. It is well established practice in telephone systems of all sizes that the dialling of the single digit ,0 shall secure connectionwithan operator volved the setting aside of the 0? level for connections to. Operators, and this necessn tates' the use of" an additional rank of switches in order to give ful'llhundred line capacity; This, in"v the particular case of an exchange of from 90-100 lines maybe a serious drawback, and it is one object of the invention. to provide. an arrangement whereby the full capacity of thejsw'itch bank;

still adhering to the oifiemploying the dialling may be retained while accepted practice of 0 to obtairi connection with an operator.-

According to. the invention, connection is obtained with an operator by dialling 0"j,'

but not over the 0 level of thedrop'back switch, and connections! with the contacts,

. in the 90 level may bemade by dialling 0 attertheswitchhas"- droppedback-in' response to the dialling off aparticular critical digit.

The invention will be better understood from the following methods of carrying it into eliect, reference being had tothe ae; companying drawings, comprising Figs.- 1, 2 and 3. 1

Fig. 1 shows a 100-point switch and Fig.

' 2 a 200-point switch andf'it willbe under-1 stood that a number ,otjdetailed modifications an be made'b'y thosefskilled in the art without departing from the spirit of theinvention. Fig. 3 a-subscribers; station T and associated lineswitch LS which has actelephone:

butin systems using 100 point has generally inx-T 'terial', and for the sake of example, it will be assumed that it is 6. It the system is assumed to comprise, 10,0 lines, the subscribers will in every case dial three digits, the first of which will be 6, but only a single rank of 100-point switches will be required; In order to obtain access to the operator,

' QFFILCE I l1owever,the single digit 0 will be dialled.

hen a subscriber initiates a call by re moving his receiver, his lineswitch LS will operate in the well knownmanner to seize a free connector switch, which'it will be assumed is that shown Fig. l. In response thereto, relay A will operate the sub-- scriber will receive dial tonefrom the'dial" tone conductor DT, over normally closed post springs NP3, i make-before-break springscontrolledby armature 11 5 of relay 11, lower winding of relay A to the lower speaking conductor. Relay A. at armature 1011 completes a circuit for release relay B which energizes and atflarmature 105 earths the release trunk conductor 130, at armature 103 earths the motor start-lead 129, at armature 104a completes a circuit for the lamp P. G. over the normally closed off-normal springs ONS, and'at armature 106. prepares the impulsing circuits in the usual manner. The calling subscriber now proceeds to dial the digit .6, whereupon six impulses are transmitted to the vertical magnet VM over the. slow acting series relay C. Relay C energizes and remains operated throughout the digit and at armature 108 completes an alternate impulsing circuit overthe operated ofi normal springs, the] lamp; P. G. at this time being extinguished due to the opening of the oft-normal springs; [Inresponse' to the'operation' of the vertical magnet, the

wipers are stepped up to the sixth level, and on this level post springs NPl close. Accordingly, when relay C falls back, a circuit is completed for the lower winding of relay R as follows: earth, armature 104 and front contact, armature 113 and back contact, operated post springs NPl, back contact and armature 107 of relay C, lower winding of relay R to battery, a parallel circuit being completed for release magnet Z over front contact and armature 102 of impulsing relay A, operated off-normal springs, release magnet Z to battery. Relay R is a two-step relay and at this time operates its light-tensioned armature 114; only, thereby shortcircuiting its upper winding over armature 113, post springs NPl and armature 107. Release magnet Z, however, now operates and the switch is returned to normal in the usual manner, whereupon post springs NPl open, removing the short-circuit from the upper winding of relay R, which relay now operates fully over both its windings in series and locks energized over its light-tensioned armature 114 to earth on armature 10 1. Relay R at armature 115 operates the inake-before-break springs and disconnects dial tone from the lower winding of relay A, connecting in place thereof direct earth.

The calling subscriber will now proceed to dial the two digits of the wanted party, and it will be assumed that the first of these digits is again 6. The post springs NPl will operate on. the 6th level as before, but this is without effect at this ime as the initial energizing circuit of relay R is opened at armature 113. Consequently, the wipers remain opposite the 6th level into which they are operated in response to the dialing of the final digit, the operations during and subsequent to the dialing of this digit are well known and need not be de scribed at this time.

In connection with the release of the switch, however, it may be noted that if the strap 120 is connected up, last-party release of the connector will be secured, while if the strap is left disconnected release will be under the control of the calling party. In the former case it will be seen that release rela B is held ener ized as lon as the ture 115 and back contact of relay R, operated post spring NP2 to the calling lamp lead 131 extending to the operators position, over a wiper of the line switch. In addition, the post springs NP3 are operated on this level, so that dial tone is disconnect ed from the lower speaking coductor and ringing tone is connected up, to indicate to the calling party that the operator is being signalled.

The lighting of lamp L informs the operator that a call is Waiting and she plugs one end of a cord circuit (not shown) into multiple jack J of the calling subscribers line. Relay 305 operates in a circuit extending from battery in the cord circuit, sleeve of jack J, winding of relay 305, to ground, and at armatures 307 and 308 opens the line extending to the automatic switches, which thereupon release. It will be clear that if the subscriber first dials the critical digit (3 and then the digit- 0 followed by a further digit he will be able to obtain access to any subscriber whose line terminates in the 0 level, since in the case of a call to an operator the switch does not cut in on this level and the connection to the operators position is not actually made over the wipers of the switch.

Referring now to the accompanying drawings, designated Fig. 2, which shows a modification of the invention as applied to a 200-point connector it will be seen that the circuit arrangement of this switch is substantially the same as that of the l00-point connector illustrated in F1 2 1, with the exception that two re-setting relays R1 and R2 are provided instead of the single relay R, these two relays acting as auxiliary switching relays to connect up one set of wipers or the other according as to whether the call is for a subscriber in the first hundred bank or the second hundred bank. In this modification, the switch is adapted to respond to two critical digits, their value being immaterial, the choice of the digits being quite arbitrary, and for the sake of example it will be assumed that in order to obtain connection to a subscriber whose line terminates in one of the first hundred group of bank contacts, the digit is 6, the subscriber dialling this digit in every case, followed by the two digits of the subscribers line, while in order to obtain. connection to a subscriber whose line terminates in the second hundred group of bank contacts the digit is 8, the calling subscriber in each case dialling this digit followed by the two digits of the wanted party.

In the initiation of a call, assuming that it is for a subscriber in the first hundred bank, the line relay A will operate in the usual manner, and at armature 201 complete a circuit for release relay B. Relay B operates and at armature 205 earths the release trunk conductor 130, at armature 204 pro- Adi- 3,13

pares circuits for the re-setting relays vR1 and B2, and release magnet Z, and at armature prepares 206 prepares impulsing cir-.

cuits in the usual manner.

The $lll3SCIlbGI- now proceeds to dial the 1 digit 6, whereupon six impulses are sent to release magnet Z, and at armature 209 com pletes an alternative impulsing clrcult ex-' tending overthe now operated off-normal springsONS. When the. wipers are stepped up to the 6th level, post springs'NPl operate and when relay C releases a circuit is compjlet'ed for relay -R1 as follows: earth, armature 20-1 and front contact, armature 208 and ,backcontact, armatures 230 and 236 and their back contacts, operated contacts of post springs NPl, normally closed contacts of post springs NP2,back contact and armature 238, the lower winding of relay R1 tobattery, and in parallel thereto over armature 207 and front contact, operated ofli normal springs, release magnet Z to battery. Relay R1 is a two-step relay and first operates its lightwensioned armature 237, thereby short-circuiting its upper winding in the circuit extending from the left-hand terminalof the upper winding of relay R1, front contact and armature 237 armature 208 and back contact, armatures 230, 236 and their back contacts, operated contacts of post springs NPl, normal contacts of post springs NR2, back contactand armature 238, to the right-hand terminal of the upper winding of relay B1. Release magnet Z, however, operates and the switch is released in the usual manner, whereupon post springs {N1 1 return to normal and remove the short-circuit fromlthe, upper winding of relayRlso that relay Rl-op'erates fully over both its windings in series, and locks up to earth on armature 2 0-l over its light-ten v sioned-armat-ure 237;

It ;now the calllng subscriber-again dials the digit 6, the wipers will be stepped up to {the sixth level in the usual manner, but will have no efl'eot on the operation of the resetting relays as relay R1 has opened the initial energizingcircuit for both relays R1 and R2. Relay R1 when fullyoperated, at armatures 23 1, 235 and 239, connects up the wipers'243, 244: and 24-5 to the normally open contacts of the switching relay H, The subscriber now proceeds to dial the digits in the wanted partys number, and the operation of the switch including the operation of the ringing trip relay F, the test relay E and the busy relay G in the well-known manner during and subsequent to the diallingot these digits are standard and need no further description.

It new the'calli-ng Subscriber desires to obtain QCCBSSjCO a subscriber whose line teri'ninates inthe second hundred ban-k, he will ,eyerycase first dial the digit 8, the switch in the usual manner and post sprii'1gs'NP-2 will operate. On the release of relay C ,a circuit will be completed-for relay R2,

and for the release magnet Z in a similar manner to that descrlbed for the operation of {relay 'Relay R2 first operates its light-tensioned armature 231, thereby short .circuiting its upper winding, and on the release of the switch whenrelay C releases at the end or" the digit, under the control oi the release magnet Z the post springs N1 2 return to normal removing the short- .circuit from the'upper winding of relay R2,

over both its windings in series. Relay B2 atarmature 230 opens the init al energ zing circu t for both relays Bland R2 sothat twill step its wipers up to the 8th level and allowing this relay to operate fully if vthe digit 8 is again dialled, the wipers Will be stepped up to the8th level and, can be rotated into that level on receipt otthefinal. digit. Relay R2 at armatures 228, 229 and 233 connects up the wipers 2&0, 241, and. 242 to the normally opencontacts controlled by the switching relay The operation of the switch during and subsequent to the dialling of the two final digits is as before I well {known and. needs no further descriptlOl'l; I i I I I Y t In case connection .to the operator is desired, the calling subscriberadials the single digit 0. When the switch is operated to the tenth level, vnormal post springs NPZ-l operate and close a circuit fromcground at .the resting contact of armature 251 and said armature, resting contact oi armature and said armature, normal postsprings N133, conductor 131, conductor 131 ,(Fig. 3), bank contact and wiper 309 of lineswitch LS, conductor 310, lamp L, to bat tery. Lamp L lights'to inform the operator of the call and the connectionto the automatic switches is released as soon as the operator answers the call, in the same manner as previously described in connection with Figs. land 3. I I

What I claim as new and desire to secure by LettersPatent is I v 1. In a telephone system, an automatic switch, an operators position, means for operating said switch responsive to digit impulses, means responsive to a predetermined first digit forsignalling saidoperators position, and'means responsive to a different predetermined first digit for.automatically re-v leasing said switch and rendering said signalling meansinefiective in case the said first predetermined digit is then called.

2. 1111 ,atelephonesystem, an operators position, an automatic switch, means responsive ;to a particular digit for operating said switch to a particular position, and means responsive to said operation for either signalling said operators position or for preparing said switch for further operation dependent on whether said digit was the first or was preceded by a different predetermined digit.

3. In a telephone system, an operators position, an automatic switch, .ieans responsive to a predetermined digit for operating said switch to a particular position, means for signalling said operators position if said digit the initial digit of a series, and means for rendering said last means inelt'ective it said digit is preceded by a different predetermined digit.

l. In a telephone system, an automatic switch having access to subscribers lines through wipers on said switch, an operators position, means responsive to a predetermined digit for operating said switch to a particular pos'fou, means "l'ective if said digit is the first of a seri' "tor signalling said operators position independently of said wipers, and means effective it said digit is preceded by a different predetermined digit for partially operating said switch to connect with one of said subscribers lines and for rendering said signalling means inefiective.

5. In a telephone system, an automatic switch having wipers, a pair of talking conductors in said switch, means for operating said switch responsive to received digit impulses, means responsive to the receipt of a predetermined first digit for automatically returning said switch to normal, and means responsive to the release of said switch for connecting said talking conductors to said wipers, said means being eil'ective only if said digit is the first received.

6. In a telephone system, an automatic switch having a plurality of: sets of: wipers, a pair of talking conductors in said switch, means for operating said switch responsive to received digit impulses, means responsive to the receipt of a predetermined digit for automatically returning said switch. to normal, and means responsive to said last means for connecting said talking conductors to a particular one of said sets of wipers depending upon the value of said predetermined digit.

7. In a telephone system, an automatic switch having wipers, a pair of talking conductors in said switch, means responsive to a predetermined initial digit for operating said switch to a particular position, a two step relay in said switch, means responsive to said operation for partially operating said relay and for releasing said switch, and means responsive to said release for fully operating said relay to connect said talking conductors to said wipers.

8. In an automatic switch, a pair of talking conductors, two sets of wipers, a pair of two-step relays for connecting said talking conductors to said two sets of wipers respectively, means for operating said switch responsive to receive digit impulses, means responsive to a predetermined initial digit for partially operating the first of said relays and for releasing said switch, means responsive to a different predetermined initial digit for partially operating the second of said relays and for releasing said switch, and means responsive to the release of said switch for fully operating the partially operated relay to connect said talking conductors to the associated set of wipers.

9. In a telephone system, an operators position, a two motion ten-level connector switch, means for operating said switch responsive to received digit impulses, means responsive to a received digit corresponding to a particular level of said switch for signailing said opcrators position, and a group of ten subscribers lines accessible to said connector in said particular level.

10. In a, private automatic exchange employing line switches and two-motion directive connector switches, multiple connector banks comprising contacts arranged in ten groups with ten sets of contacts in each group, said banks being fully equipped with one hundred subscribers lines, an operators position, and means responsive to the operation 01" one of said connectors to a position corresponding to a particular one of said groups for signalling said operators posltlon.

11. In a private automatic exchange employing line switches and two-motion directive connector switches, multiple connector banks comprising contacts arranged in ten groups with ten sets of contacts in each group, said banks being fully equipped with one hundred subscribers lines, an operators position, and means responsive to the operation of one of said connectors to a. position opposite a particular one of said groups for either signalling said operators position or partially completing a connection to one of said subscribers lines dependent upon whether or not said operation was preceded by a preliminary operation of the connector.

In testimony whereof I have signed at Liverpool, England, this 7th day of September, 1928.

CHARLES EDMUND BEALE. 

